Exhaust silencer



Dec. 12, 1939. -E. G. GUNN EXHAUST SILENCER Filed July 50, 1937 2 Sheets-Sheet l INVENTOR Earl 6. 6207);. BY

9' W I A TTORNE Y5.

Dec. 12, 1939.

E. G. GUNN EXHAUST SILENCER Filed July 30, 1937 2 Sheets-Sheet 2 INVENTOR 0% m an m A a g W M F Patented Dec. 12, 1939.

PATENT OFFICE EXHAUST snnncaa Earl G. Gunn,

Jackson,

Mich, assignor to Walker Manufacturing Company, Racine, Wis., a corporation of Wisconsin Application July 30, 1937, Serial No. 15s,5s1

8 .Claims.

The present invention relates generally to exhaust silencers for internal combustion engines of motor vehicles. More particularly it relates to an improved form of exhaust silencer which embodies aretroverted substantially continuous exhaust passage and which includes as an integral portion of the construction, a resonating chamber constructed and arranged to eliminate certain objectionable sounds resulting from normal operation of the motor with a conventional The exhaust silencer of the present invention is of what is conventionally known as, the three tube type, as contrasted to a straight tube mufiier. Silencers of this generic type usually include three longitudinally disposed tubes, one of which connects with the exhaust manifold, another connects with the tail pipe, and a third serves to provide an interconnection between the first two. Communication between the inlet tube and the outlet tube through the return tube is ac.- complished by means of cross-0v rs which crossovers comprise fittings which s rve to change the direction of flow of the gas through an angular distance of 180.

The present invention contemplates the provision of a resonator chamber interiorly of thecasing which surrounds these tubes and includes an opening or pipe establishing communication between one of the cross-overs and this resonator chamber.

It is well recognized that resonating chambers of this generic type have a silencing effect which depends upon three co-related factors, namely, the volume of the chamber, the size of the opening, and the length of the tube which establishes communication with the chamber. While it will be readily understood that diflerent types of motors running at different speeds in various setups produce certain objectionable sounds during ciated that the particular resonator chamber may be so proportioned, constructed, and arranged that this resonator chamberniay .serve to eliminate the undesirable sound emanating from a particular construction and arrangement.

Still further, the present invention contemplates the provision of an enclosed chamber in the opposite end of the muiller construction from the resonator chamber, through which last mentioned chamber the outlet pipe of the muiller passes. The present invention contemplates the provision of tangential openings provided in the outlet pipe throughout the zone of the pipe which passes through this last mentioned chamber in the normal ranges of operation, it will be appreorder that this chamber may also act as a resonator for eliminating certain undesirable sounds.

Many other and further objects, advantages, and features of the present invention will become clearly apparent from the following specification when considered in connection with the accompanying drawings forming a part thereof.

In the drawings:

Figure l is a longitudinal sectional view through a muiiier construction embodying the improvements of the present invention.

Fig. 2 is a transverse sectional view taken substantially on the line 2-2 of Fig. 1 illustrating in detail the construction and arrangement of the tubes interiorly of the mufiler, the cross-over duct and the tube communicating with the resonator chamber.

Fig. 3 is an enlarged fragmentary transverse sectional view through one of the louvered tubes illustrating the manner in which the vents are provided therein.

Fig. 4 is a longitudinal sectional view through a somewhat modified form of silencer construction embodying the improvements of the present invention,

Fig. 5 is a transverse sectional view taken substantially on the line 55 of Fig. 4 illustrating in detail cross-sectional configuration of the silencer disclosed therein.

It will be readily apparent to those skilled 3 in the art that the silencer construction disclosed in the drawings of the present application may be constructed in many and various different ways and forms and 'yet at the same time embody therein the improvements of the present invention. It has been found preferable, however, to fabricate the silencer construction in the manner shown in the drawings and as hereinafter described in detail.'

As is conventional in constructions of this general character, the silencer as a whole includes a generally cylindrical sheet metal casing 5 which a is closed and sealed at its. ends by means of partitioning members or end walls 6 and I, respectively. interiorly, the casing is provided with a pair of spaced baflies 8 and 9 which serve the function of dividing the interior of the casing into compartments of predetermined size and also serve the purpose of supporting the tubes of the silencer in the manner described in detail below.

It will of course be apparent that in constructing an exhaust silencer of the type shown in the' drawings the volume of the various chambers formed interiorly of the casing may be conveniently regulated by adjusting the battles inprehaust gases include an inlet tube l0 which passes through the end wall 6 of the casing in sealed relation with respect thereto and which is adapted, as is conventional in constructions of this general character, to be connected by a suitable pipe to the exhaust manifold of the motor with which the silencer is adapted to be used.

As is clear by reference to Fig. 1 of the drawings, this inlet tube' In is not only supported in sealed relation to the end wall member 6 but is also supported in sealed relation with respect to the partition members 8 and 9.

The outlet or discharge tube II is mounted in sealed relation to and passes throughthe end wall partition member and is likewise supported in the, baffles or partitioning members 9 and 8 in substantially the same manner as the inlet tube i0. Also mounted in the baffle members 8 and 9 is the third or intermediate tube I? seen in dotted lines in Fig.2.

From the foregoing, it will be appreciated tha the baiile members 8 and 9 serve to divide the casing structure generally into three compartments l3, I4 and i5, respectively, the size of which may be conveniently regulated by the particular position of the baffle members 8 and 9. The rear end of the inlet tube 0 terminates approximately at the baflie member 9 and likewise the rear end of the intermediate tube I2 terminates at this baiiie. Communication between the respective rear ends of these tubes is established by means of a cross-over H which may be in the form of a semi-circular coupling member which is preferably flanged and welded to the baflle 9 in order to provide a conduit of substantially uniform cross sectional area establishing communication between the rear end of the tube i0 and the rear end of the tube |2 A substantially similar crossover member lil'similarly serves to establish communication between the forward end of the outlet pipe H and the rear end of the intermediate tube. i2. a

It will be readily seen that the cross-over I1 is located wholly within the chamber i3 but no communication is afforded between the interior of the cross-over l1 and the interior of the chamber l3. However, the cross-over i8 is located wholly within the interior of the chamber l5 and,

in substantially its mid-portion, it is provided with a projecting substantially cylindrical tube I 9 which establishes communication between the interior of this cross-over member l8 and the in terior of the chamber l5. The chamber |5 thus constitutes a resonator chamber which will serve to silence sounds of certain frequenciesf The function of this resonator in the eliinination of sounds from the motor depends, as mentioned above, upon its volume, the diameter of the pipe l9 and the length of thepipe I9. It will be readily appreciated that these factors may be controlled in order to obtain maximum effectiveness in 'a particular installation. a

The portions of the tubes IO, N and I2 which are located within the chamber l4 preferably are provided with tangential louvers 20 which have been found ,to be particularly eifective in the elimination of certain sounds. The portion of the tube II which lies within the closed chamber 3 is preferably provided with louvers 2| which. construction has likewise been particularly effective in the elimination of sounds of certain frequencies.

In the form of the invention illustrated in Figs. 4 and 5, a somewhat modified form of muflier construction is illustrated, but it will be seen that the exhaust silencer construction shown therein embodies the same inventive improvements set forth in connection with the preferred form of the invention illustrated in Figs. 1 to 3, inclusive. In this form the silencer comprises a generally oval sheet metal housing 25 which has intermediate headers 30 and 3| welded in place therein. These headers 30 and 3| are each spaced inwardly from the axial ends of the nousing 25 in order to provide for the chambers hereinafter described. The device shown comprises an inlet tube 33 which passes through and is supported in an end wall member 34 serving to close the said end of the casing 25. An outlet tube 35 extends through and is supported in an end wall member 36 which serves to close the rear end of the casing 25. The inlet tube 35 passes through the partition members 30 and 3| and is mounted in sealed relation with respect thereto, and in a similar manner the inlet tube 33 passes through these partitions and is sealed with respect thereto. It will be noted that the inlet tube terminates substantially flush with the partition member 3| and the outlet tube terminates substantially flush with the partition member 30. A return tube 31 is mounted in the partition members 30 and 3| and is connected with the inlet tube 33 and outlet tube 35 by means of cross-overs 38 and 39, re-

spectively, which are similar in construction and arrangement to the cross-overs l1 and I8 disclosed in connection with the preferred embodiment of the invention.

It will be appreciated that the partition member 30 together with the casing 25 and end wall member 34 forms an enclosed chamber 40 which communicates with the exhaust passage through a projecting pipe or tube 4| in the cross-over 39, thus providing a sound resonator chamber in communication with the exhaust passage. As was the case in connection with the preferred embodiment of the invention, .the inlet tube, outlet tube, and return tube are each provided with a .series of louvers 44 which permit the escape of wall 36 may similarly be provided with a series of louvers if desired.

From the foregoing it will be readily understood that the exhaust silencer illustrated and described is an extremely simple, cheap and easily fabricated construction which may conveniently be proportioned to operate effectively with many and various types of motors.

Many modifications of the above described construction falling. within the scope of the invention as defined in the subjoined claims will be clearly apparent to those skilled in the art.

What is claimed is:

1. In an exhaust silencer construction having a plurality of tubes and having cross-overs interconnecting said tubes to define a retroverted exhaust passage havinga substantially uniform cross-sectional area throughout its-length, a casing defining a sound resonator chamber, surrounding and enclosing one of said cross-overs, and means defining an opening between the interior of said cross-over andsaid chamber.

2. In an exhaust silencer construction having a plurality of laterally'spaced tubes and having 15 cross-overs extending transversely of and interconnecting said tubes to define a continuous retroverted exhaust passage, a casing surrounding said tubes, said casing having a chamber formed therein which encloses one of said cross-overs, said one cross-over having an opening in the wall thereof establishing communication between the interior of said one cross-over and said chamber.

3. In an exhaust silencer construction having a plurality of laterally spaced tubes and having cross-overs extending transversely of and interconnecting said tubes to define a substantially continuous retroverted exhaust passage of sub stantially uniform cross-sectional area throughout, a casing surrounding said tubes, a sound resonator chamber formed interiorly of said casing and enclosing one of said cross-overs, and a tube associated with said one of said cross-overs, one end of said tube opening directly into said chamber and the other end thereof opening directly into said one cross-over.

4. In an exhaust silencer construction having a plurality of laterally spaced tubes and having cross-overs extending transversely of and inter connecting said tubes whereby to define a retroverted exhaust passage, a casing surrounding said tubes, bafiles within said casing serving to support said tubes and serving to divide said casing interiorly into a plurality of closed chambers, one of said cross-overs being positioned in one of said chambers, and means defining an opening in said one of said cross-overs directly com municating the interior of said one of said chambers with the interior of said one cross-over.

5. In an exhaust silencer construction having a plurality of laterally spaced tubes and having cross-overs extending transversely of and interconnecting saidtubes whereby to define a retroverted exhaust passage, a casing surrounding said tubes, bafiles within said casing serving to support said tubes and serving to divide said casing interiorly into a plurality of closed chambers, one of said cross-overs being positioned in one of said chambers, and means defining an opening in said one of said cross-oversdirectly communicating the interior of said one of said chambers with the interior of said one cross-over, and

louvres in said tubes establishing communication between the said exhaust passage and the remainder of the chambers formed in said casing.

6. In an exhaust silencer construction having a plurality of laterally spaced tubes and having cross-overs extending transversely of and interconnecting said tubes whereby to define a retroverted exhaust passage, baifles within said casing serving to support said tubes and divide said casing interiorly into a plurality of closed chambers, a branch tube having one end opening directly into one of said chambers and the other end opening directly into one of said cross-overs whereby to provide a sound resonator chamber in communication with said exhaust passage.

7. An exhaust silencer comprising a casing having end Walls closing the same at its opposite ends, a pair of baffles interiorly of said casing dividing the same into a front compartment, a central compartment and a rear compartment, an inlet tube passing through one of said end walls and both of said baffles and mounted in sealed relation with respect thereto, an outlet tube passing through the other of said end walls and said bafiies and likewise in sealed relation with respect thereto, an intermediate tube extending through said central compartment and baffies and supported in said baffles in sealed relation with respect thereto, a cross-over interconnecting the forward end of said outlet tube and the forward end of said intermediate tube, said cross-over lying within said forward compartment, and means defining direct communication between the interior of said cross-over and the interior of said forward compartment where- '.by to provide a sound resonator.

8. An exhaust silencer comprising a casing having end walls closing the same at its opposite ends, a pair of baffles interiorly of said casing dividing the same into a front compartment, a central compartment and a rear compartment, an inlet tube passing through one-of said end walls and both of said baifles and mounted in sealed relation with respect thereto, an outlet tube passing through the other of said end walls and said bafiles and likewise in sealed relation with respect thereto, an intermediate tube extending through said central compartment and baflies and supported in said baffles in sealed relation with respect thereto, a cross-over interconnecting the forward end of said outlet tube and the forward end of said intermediate tube, said crossover lying within said forward compartment, means defining direct communication between the interior of said cross-over and the interior of said forward compartment whereby to provide a sound resonator, and louvres in the portionsof said inlet, outlet and intermediate tubes within said central compartment to establish communication between the interior of said tubes and saidcentral compartment.

EARL G. GUNN. 

